Move stress_cache to the tools directory

net/tools/stress_cache/stress_cache.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This is a simple application that stress-tests the crash recovery of the disk
 // cache. The main application starts a copy of itself on a loop, checking the
 // exit code of the child process. When the child dies in an unexpected way,
 // the main application quits.
 
 // The child application has two threads: one to exercise the cache in an
@@ skipping 273 matching lines @@
   long int iteration = strtol(argv[1], &end, 0);
 
   if (!StartCrashThread()) {
     printf("failed to start thread\n");
     return kError;
   }
 
   StressTheCache(iteration);
   return 0;
 }